Fix traceback in Python runner plugins

Plamascript.Runner is the base of python krunner plugins. These plugins
implement the C++ signals prepare, teardown, createRunOptions and
reloadConfiguration in actual methods (the signal wiring happens in
pyrunner.py which is the loading component). As a result of this calls
to any of these methods will fall through to plasmascript.Runner whenever
the actual runner does not implement them. However plasmascript.Runner is
missing the implicit 'self' argument such that one gets silly python
backtraces like

File "/usr/share/kde4/apps/plasma_scriptengine_python/pyrunner.py", line 90, in reloadConfiguration
self.pyrunner.reloadConfiguration()

To prevent this from happening the functions now have the implicit self
argument.

Also see:
https://bugs.launchpad.net/ubuntu/+source/kde-workspace/+bug/1258088


REVIEW: 114314